Thursday, March 20, 2008

Salmonella, It's In The Leaves

Sherri (the other one) was commenting about how bacteria "can get drawn into the roots of greens and lettuces." She warns us ... it could be in the leaves!

I vaguely recalled something about that. From a quick search:

Assessment of Contamination Potential of Lettuce by Salmonella enterica Serovar Newport Added to the Plant Growing Medium, Journal of Food protection, July 2007

Here's the abstract:

"The capacity of Salmonella enterica serovar Newport to contaminate Romaine lettuce (Lactuca sativa L. cv. Nogal) via the root system was evaluated in 17-, 20-, and 33-day-old plants. Apparent internalization of Salmonella via the root to the above-ground parts was identified in 33- but not 17- or 20-day-old plants and was stimulated by root decapitation. Leaves of lettuce plants with intact and damaged roots harbored Salmonella at 500 ± 120 and 5,130 ± 440 CFU/g of leaf, respectively, at 2 days postinoculation but not 5 days later. These findings are first to suggest that Salmonella Newport can translocate from contaminated roots to the aerial parts of lettuce seedlings and propose that the process is dependent on the developmental stage of the plant."

It looks like conditions have to be ripe for leaf contamination ... tainted soil, roots attached, longer growing period ... but it's not far-fetched. And I'm guessing organic produce is not immune.

So what if, as Sherri said, Alamosa's salmonella-contaminated water was used to irrigate edible plants? The more you think about it, the more widespread a problem like this becomes.

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Photo above from Perdue University Entomology Extension.

There was another photo on that page that set off my ewwww factor - the one to the right.